<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .item {
      position: fixed;
      width: 100px;
      height: 100px;
      left: 0;
      top: 0;
      background-color: #f00;
    }

    .box2 {
      left: 20px;
      top: 20px;
      background-color: #0f0;
      z-index: -1;
    }

    .box3 {
      left: 40px;
      top: 40px;
      background-color: #00f;
    }

    .info {
      position: absolute;
      z-index: 999;
    }
  </style>
</head>
<body>
  
  <div class="item box1">1</div>
  <div class="container">
    <div class="item box2">
      <div class="info">哈哈哈</div>
      <div>呵呵呵</div>
    </div>
  </div>
  <div class="item box3">3</div>

</body>
</html>